.\" $OpenBSD: evp.3,v 1.32 2024/08/30 07:03:19 tb Exp $
.\" full merge up to: OpenSSL man7/evp 24a535ea Sep 22 13:14:20 2020 +0100
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.Dd $Mdocdate: August 30 2024 $
.Dt EVP 3
.Os
.Sh NAME
.Nm evp
.Nd high-level cryptographic functions
.Sh SYNOPSIS
.In openssl/evp.h
.Sh DESCRIPTION
The EVP library provides a high-level interface to cryptographic
functions.
.Pp
.Xr EVP_SealInit 3
and
.Xr EVP_OpenInit 3
provide public key encryption and decryption to implement digital
"envelopes".
.Pp
The
.Xr EVP_DigestSignInit 3
and
.Xr EVP_DigestVerifyInit 3
functions implement digital signatures and Message Authentication Codes
(MACs).
Also see the older
.Xr EVP_SignInit 3
and
.Xr EVP_VerifyInit 3
functions.
.Pp
Symmetric encryption is available with the
.Xr EVP_EncryptInit 3
functions.
The
.Xr EVP_DigestInit 3
functions provide message digests.
.Pp
Authenticated encryption with additional data (AEAD) is available with
the
.Xr EVP_AEAD_CTX_init 3
functions.
.Pp
The
.Fn EVP_PKEY_*
functions provide a high-level interface to asymmetric algorithms.
To create a new
.Vt EVP_PKEY ,
see
.Xr EVP_PKEY_new 3 .
.Vt EVP_PKEY Ns s
can be associated with a private key of a particular algorithm
by using the functions described in the
.Xr EVP_PKEY_set1_RSA 3
page, or new keys can be generated using
.Xr EVP_PKEY_keygen 3 .
.Vt EVP_PKEY Ns s
can be compared using
.Xr EVP_PKEY_cmp 3
or printed using
.Xr EVP_PKEY_print_private 3 .
.Pp
The
.Fn EVP_PKEY_*
functions support the full range of asymmetric algorithm operations:
.Bl -bullet
.It
For key agreement, see
.Xr EVP_PKEY_derive 3 .
.It
For signing and verifying, see
.Xr EVP_PKEY_sign 3 ,
.Xr EVP_PKEY_verify 3 ,
and
.Xr EVP_PKEY_verify_recover 3 .
However, note that these functions do not perform a digest of the
data to be signed.
Therefore, normally you would use the
.Xr EVP_DigestSignInit 3
functions for this purpose.
.It
For encryption and decryption see
.Xr EVP_PKEY_encrypt 3
and
.Xr EVP_PKEY_decrypt 3 ,
respectively.
However, note that these functions perform encryption and decryption only.
As public key encryption is an expensive operation, normally you
would wrap an encrypted message in a digital envelope using the
.Xr EVP_SealInit 3
and
.Xr EVP_OpenInit 3
functions.
.El
.Pp
The
.Xr EVP_BytesToKey 3
function provides some limited support for password based encryption.
Careful selection of the parameters will provide a PKCS#5 PBKDF1
compatible implementation.
However, new applications should typically not use this (preferring, for
example, PBKDF2 from PCKS#5).
.Pp
The
.Xr EVP_EncodeInit 3
family of functions provides base64 encoding and decoding.
.Sh SEE ALSO
.Xr ASN1_item_digest 3 ,
.Xr ASN1_item_sign 3 ,
.Xr BIO_f_cipher 3 ,
.Xr BIO_f_md 3 ,
.Xr CMAC_Init 3 ,
.Xr CMS_encrypt 3 ,
.Xr CMS_sign 3 ,
.Xr crypto 3 ,
.Xr d2i_PKCS8PrivateKey_bio 3 ,
.Xr d2i_PrivateKey 3 ,
.Xr EVP_AEAD_CTX_init 3 ,
.Xr EVP_aes_128_cbc 3 ,
.Xr EVP_BytesToKey 3 ,
.Xr EVP_camellia_128_cbc 3 ,
.Xr EVP_chacha20 3 ,
.Xr EVP_CIPHER_CTX_ctrl 3 ,
.Xr EVP_CIPHER_CTX_get_cipher_data 3 ,
.Xr EVP_CIPHER_CTX_init 3 ,
.Xr EVP_CIPHER_CTX_set_flags 3 ,
.Xr EVP_CIPHER_do_all 3 ,
.Xr EVP_CIPHER_meth_new 3 ,
.Xr EVP_CIPHER_nid 3 ,
.Xr EVP_des_cbc 3 ,
.Xr EVP_DigestInit 3 ,
.Xr EVP_DigestSignInit 3 ,
.Xr EVP_DigestVerifyInit 3 ,
.Xr EVP_EncodeInit 3 ,
.Xr EVP_EncryptInit 3 ,
.Xr EVP_MD_CTX_ctrl 3 ,
.Xr EVP_MD_nid 3 ,
.Xr EVP_OpenInit 3 ,
.Xr EVP_PKCS82PKEY 3 ,
.Xr EVP_PKEY_asn1_get_count 3 ,
.Xr EVP_PKEY_asn1_new 3 ,
.Xr EVP_PKEY_check 3 ,
.Xr EVP_PKEY_cmp 3 ,
.Xr EVP_PKEY_CTX_ctrl 3 ,
.Xr EVP_PKEY_CTX_get_operation 3 ,
.Xr EVP_PKEY_CTX_new 3 ,
.Xr EVP_PKEY_CTX_set_hkdf_md 3 ,
.Xr EVP_PKEY_decrypt 3 ,
.Xr EVP_PKEY_derive 3 ,
.Xr EVP_PKEY_encrypt 3 ,
.Xr EVP_PKEY_get_default_digest_nid 3 ,
.Xr EVP_PKEY_keygen 3 ,
.Xr EVP_PKEY_meth_get0_info 3 ,
.Xr EVP_PKEY_meth_new 3 ,
.Xr EVP_PKEY_new 3 ,
.Xr EVP_PKEY_print_private 3 ,
.Xr EVP_PKEY_set1_RSA 3 ,
.Xr EVP_PKEY_sign 3 ,
.Xr EVP_PKEY_size 3 ,
.Xr EVP_PKEY_verify 3 ,
.Xr EVP_PKEY_verify_recover 3 ,
.Xr EVP_rc4 3 ,
.Xr EVP_SealInit 3 ,
.Xr EVP_sha1 3 ,
.Xr EVP_sha3_224 3 ,
.Xr EVP_SignInit 3 ,
.Xr EVP_sm3 3 ,
.Xr EVP_sm4_cbc 3 ,
.Xr EVP_VerifyInit 3 ,
.Xr HMAC 3 ,
.Xr OCSP_basic_sign 3 ,
.Xr OCSP_request_sign 3 ,
.Xr PEM_get_EVP_CIPHER_INFO 3 ,
.Xr PEM_read_bio_PrivateKey 3 ,
.Xr PKCS12_create 3 ,
.Xr PKCS5_PBKDF2_HMAC 3 ,
.Xr PKCS7_encrypt 3 ,
.Xr PKCS7_sign 3 ,
.Xr RSA_pkey_ctx_ctrl 3 ,
.Xr SSL_CTX_set_tlsext_ticket_key_cb 3 ,
.Xr X509_ALGOR_set0 3 ,
.Xr X509_check_private_key 3 ,
.Xr X509_digest 3 ,
.Xr X509_get_pubkey 3 ,
.Xr X509_PUBKEY_set 3 ,
.Xr X509_sign 3 ,
.Xr X509_to_X509_REQ 3
